1. Technical Field of the Invention
The present invention relates to a stacked assembly having a bus bar and, more particularly, to an arrangement wherein a top insulating plate is securely held to the lower substrate without the need for welding.
2. Art Relating to the Invention
Conventionally, electrical connection boxes are used as connection junction points for wire harnesses and the like while also housing various electronic circuits, electronic components, and the like for automobiles.
Electrical connection boxes often house a stacked assembly as shown in FIG. 5. In FIG. 5, stacked assembly 51 includes bus bar stacked substrate 52, insulative plate 53, and plurality of solid-core wires 54. Bus bar stacked substrate 52 forms one portion of an internal circuit and includes a plurality of stacked insulative substrates 56, 57, 58. Bus bars 61 are fixed above the insulative substrate 56, between insulative substrates 56, 67, 58, and below insulative substrate 58. Bus bars 61 include plate-shaped bus bar tabs 62, which are bent perpendicular to both the direction in which bus bars 61 are laid, and supporting bus bar tabs 63. Bus bar tabs 63 have sections 63a which form a pincer shape for connecting to solid core wires 54.
Insulative plate 53 is mounted on top of a portion of bus bar stacked substrate 52. Insulative plate 53 is formed in a plate shape that covers a portion of insulative substrate 56 that portion being the part that has bus bar tabs 63. Tab holders 66 are formed in insulative plate 53 and align with bus bar tabs 63. Tab holders 66 are formed with tab insertion openings 69, which have widths that are slightly greater than the widths of bus bar tabs 63. When insulative plate 53 is mounted on bus bar stacked substrate 52, bus bar tabs 63 are inserted through tab insertion openings 69. When this is done, the ends of supporting sections 63a are projected from the upper end of tab holder 66.
Solid-core wires 54 are connected to bus bar tabs 63. In this process of assembly, the insulative covering on solid-core wire 54 is cut away by supporting section 63a, thus forming an electrical connection between solid-core wire 54 and bus bar tab 63.
With the above operation, bus bar 61 and solid-core wire 54 are electrically connected, and an electrical circuit is formed on the upper surface of insulative plate 53, thus forming the internal circuit in stacked assembly 51.
Stacked assembly 51 is interposed and loosely fixed between an upper case and a lower case (not shown in the figure) and is housed inside the electrical connection box.
One of the problems associated with stacked assembly 51 is that insulative plate 53 can disengage from bus bar stacked substrate 52 thereby also disengaging solid-core wires 54. This can result in time-consuming operation of re-wiring solid-core wires 54.
Also, stacked assembly 51, housed in the electrical connection box, is only loosely held by the upper case and the lower case. Thus, bus bar stacked substrate 52 and insulative plate 53 can become misaligned due to the leeway provided by the clearance and the vibrations that are inherent in an automobile when it is being operated. This can lead to bad connections between bus bars 61 and solid-core wires 54. This also requires re-wiring solid-core wires 54.
One measure that has been taken to prevent these types of bad connections is to weld bus bar substrate 52 to insulative plate 53. However, this requires special equipment to perform welding and also requires a larger number of production steps for the welding operation, leading to increased production costs. Furthermore, extra space is required to provide for welding spots, leading to larger dimensions for stacked assembly 51.